1. Field of the Invention
The invention relates to a diagnostic method for recognizing combustion misfiring in an internal-combustion engine.
2. Description of the Related Art
The requirement to recognize misfiring under all the operating conditions of an internal-combustion engine, to make it possible to counteract increased emissions of harmful materials associated therewith or to perform protective functions with a catalytic converter, have increasingly becoming part of the corresponding regulations. Various methods have already become known for recognizing such combustion misfiring, such as, for example, the evaluation of erratic running or a lambda-probe signal or monitoring of the ignition current, etc.
It has been shown, however, that none of these methods can provide generally valid evidence of combustion misfiring. On the one hand, there is the problem that one method does not work with sufficient accuracy in all load and rotational-speed ranges, as, for example, in the consideration of erratic running. On the other hand, in some other methods, there is the problem that no reliable information about a proper combustion can be obtained, since only sub-functions necessary for the combustion method are diagnosed, as, for example, in ignition-current diagnosis.